import * as THREE from 'three';


class CSS2DObject extends THREE.Object3D {

    constructor( element = document.createElement( 'div' ) ) {

        super();
        this.element = element;
        this.element.style.position = 'absolute';
        this.element.style.userSelect = 'none';
        this.element.setAttribute( 'draggable', false );
        this.addEventListener( 'removed', function () {

            this.traverse( function ( object ) {

                if ( object.element instanceof Element && object.element.parentNode !== null ) {

                    object.element.parentNode.removeChild( object.element );

                }

            } );

        } );

    }

    copy( source, recursive ) {

        super.copy( source, recursive );
        this.element = source.element.cloneNode( true );
        return this;

    }

}

CSS2DObject.prototype.isCSS2DObject = true; //

const _vector = new THREE.Vector3();

const _viewMatrix = new THREE.Matrix4();

const _viewProjectionMatrix = new THREE.Matrix4();

const _a = new THREE.Vector3();

const _b = new THREE.Vector3();

class CSS2DRenderer {

    constructor( parameters = {} ) {

        const _this = this;

        let _width, _height;

        let _widthHalf, _heightHalf;

        const cache = {
            objects: new WeakMap()
        };
        const domElement = parameters.element !== undefined ? parameters.element : document.createElement( 'div' );
        domElement.style.overflow = 'hidden';
        this.domElement = domElement;

        this.getSize = function () {

            return {
                width: _width,
                height: _height
            };

        };

        this.render = function ( scene, camera ) {

            if ( scene.autoUpdate === true ) scene.updateMatrixWorld();
            if ( camera.parent === null ) camera.updateMatrixWorld();

            _viewMatrix.copy( camera.matrixWorldInverse );

            _viewProjectionMatrix.multiplyMatrices( camera.projectionMatrix, _viewMatrix );

            renderObject( scene, scene, camera );
            zOrder( scene );

        };

        this.setSize = function ( width, height ) {

            _width = width;
            _height = height;
            _widthHalf = _width / 2;
            _heightHalf = _height / 2;
            domElement.style.width = width + 'px';
            domElement.style.height = height + 'px';

        };

        function renderObject( object, scene, camera ) {

            if ( object.isCSS2DObject ) {

                _vector.setFromMatrixPosition( object.matrixWorld );

                _vector.applyMatrix4( _viewProjectionMatrix );

                const visible = object.visible === true && _vector.z >= - 1 && _vector.z <= 1 && object.layers.test( camera.layers ) === true;
                object.element.style.display = visible === true ? '' : 'none';

                if ( visible === true ) {

                    object.onBeforeRender( _this, scene, camera );
                    const element = object.element;

                    if ( /apple/i.test( navigator.vendor ) ) {

                        // https://github.com/mrdoob/three.js/issues/21415
                        element.style.transform = 'translate(-50%,-50%) translate(' + Math.round( _vector.x * _widthHalf + _widthHalf ) + 'px,' + Math.round( - _vector.y * _heightHalf + _heightHalf ) + 'px)';

                    } else {

                        element.style.transform = 'translate(-50%,-50%) translate(' + ( _vector.x * _widthHalf + _widthHalf ) + 'px,' + ( - _vector.y * _heightHalf + _heightHalf ) + 'px)';

                    }

                    if ( element.parentNode !== domElement ) {

                        domElement.appendChild( element );

                    }

                    object.onAfterRender( _this, scene, camera );

                }

                const objectData = {
                    distanceToCameraSquared: getDistanceToSquared( camera, object )
                };
                cache.objects.set( object, objectData );

            }

            for ( let i = 0, l = object.children.length; i < l; i ++ ) {

                renderObject( object.children[ i ], scene, camera );

            }

        }

        function getDistanceToSquared( object1, object2 ) {

            _a.setFromMatrixPosition( object1.matrixWorld );

            _b.setFromMatrixPosition( object2.matrixWorld );

            return _a.distanceToSquared( _b );

        }

        function filterAndFlatten( scene ) {

            const result = [];
            scene.traverse( function ( object ) {

                if ( object.isCSS2DObject ) result.push( object );

            } );
            return result;

        }

        function zOrder( scene ) {

            const sorted = filterAndFlatten( scene ).sort( function ( a, b ) {

                if ( a.renderOrder !== b.renderOrder ) {

                    return b.renderOrder - a.renderOrder;

                }

                const distanceA = cache.objects.get( a ).distanceToCameraSquared;
                const distanceB = cache.objects.get( b ).distanceToCameraSquared;
                return distanceA - distanceB;

            } );
            const zMax = sorted.length;

            for ( let i = 0, l = sorted.length; i < l; i ++ ) {

                sorted[ i ].element.style.zIndex = zMax - i;

            }

        }

    }

}

export {
    CSS2DObject,
    CSS2DRenderer
}
